Throttle valve operating mechanism



Nov. 10, 1953 c. E. KENNEY 2,658,434

THROTTLE VALVE OPERATING MECHANISM Filed March 29, 1949 m/wwm Patented Nov. 10, 1953 UNITED STAT ES; PAT OFF 161E THROTTLE-VALVE OPERATING MECHANISM Glarencc E, Kenney, West Allis, Wis'., assig npr-to Allis.- Qhalmers, Manuf apturing- Company, Milwaukee, Wis, a. corporation of Delaware Application-March29, 1949, Serial No. 84,031

4 Claims, 1

Thisinvention relatesto an operating mechanism for a throttle valve and has for a principal, object the provision of new and improved apparatus of this type.

A more specific object of the invention is to provide new and improvedv means for operating the throttle valve of an elastic fluid; turbine.

Another object of the invention is.- to provide an operating mechanism for a throttle valve which: will permitthe closing of thethrottle valve in response to an operating condition of the turbine regardless of the. setting of the member controlling the operating mechanism.

Still another object of' the invention is to pro: vide an operating mechanism for a throttle valve which: will not open the throttle valve after the valve has been tripped and the tripping device reset until the control member has. been brought to a position corresponding. tothe closed. position ofthe throttle valve. This is to assure. gradual restoration of pressure of the motive. fluid under full manual control.

Other objects will appear hereinafter as the description of the invention proceeds,

The novel features of the invention and howthe objects are attained will appear more. fully. from this specification and the accompanying drawing showing one embodiment of the invention and forming a part of this application, and. all these novel features. are intended to be pointed out in the claims.

In the drawing:

The figure is a diagrammatic view of a turbine equipped with a throttle valve operating mecha-. nism embodying this invention, the throttle valve. and operating mechanism therefor being shown in, section.

Referring to the drawing more in detail, a throttle valve, here shown as a turbine throttle valve 1, is disposed in a conduit 2; through which elastic fiuid under pressure, which may be steam, is supplied to a turbine 3. The throttle valve 5 is operated in opening and closing direction by motor means 4 which is actuated by fluid under pressure. The value of the fluid pressure applied to the motor means 4 is controlled by pilot valve means 5 which, being connected to a floating lever 6, is movable in response to movements of both the throttle valve l and a control member I which may be manually operated.

The throttle valve 1 may be tripped closed when an undesirable operating condition exists in the turbine 3, for example, when the turbine oversp ds t o dens r c m d o s. Th throttle valve I is here shown as adapted to be closed; when the turbine 3; overspeeds, through the action of an overspeed trip mechanism 8;, The overspeed trip mechanism 8, controls the opening of; a fluid pressure operable control valve. 9 which controls the release of fluid pressure iron ating the, throttle valve I; is; a known; arrange;

ment and; other embodimcntsc will be apparent to those skilled in the art. The. motor means, 4 comprises a piston ll connected to the. throttle valve Iv by a rod t2 Thepiston H is slidably enclosed in a cylinder i3 and; is biased in valveclosing direction by any suitable means, herev shown as a spring 14; disposed in the cylinder i3; and acting on the. piston. H. A drain conduit I5 communicates with the cylinder i3 above the. upper limit of travel of the. piston It. The, cylinder i3 is here. shown as, formed in one end of; a casing [6. The portion of; the casing it, which is. not occupied by the cylinder 13, is divided into. two: chambers. l1: and t3. by a bulkhead lfl The. walls of the top chamber H which will be. referred to as the low pressure chamber ii, are provided with two. ports. A first port 2i provides communication with the cylinder 13, above the upper limit of travelof the piston ii. A second port, 22 cooperates with the. pilot valve means i.

Thewalls of the bottom chamber I8, which will be referred to as the high. essure chamber to, are p o i d i h. five o A rs port omm nicates. with the. cylinder l3. below the lower limit of travel of the. piston H. A second port 2!; communicates with a source of fluid pressure, here shown as a pump 25,, through a conduit 26. An orifice valve 2;] is interposed in the conduit 25. between the pump, 25 and the port 24 A third port '28;comr nur 1icates with the. pump 2 5 through a conduit, 23, 28a, The overspeed tripping mech: anism 8 is interposed between the port 28,- and the pump 25 and will, when tripped, cut ofi the supply of fluid pressure to theconduit 29. and cause the conduit 2-9 to communicate with a drain 3|. A fourth port 32 communicates with the conduit 29 through a branch conduit 33. Valve means 34 for controlling the flow of fluid throu h conduit 33 is disposed between the port 32 and the connection of conduit 33 with the conduit 29,. A fifth port 35 connects chamber H with chamber [8 when pilot valve means 5 uncovers port 2 2 Th contr alv 9 hic c n r ls h el a of fl d p essur f om the motor m an c pr se a yl ndrica valve Casing 36, extending through the bulkhead l9 and engaging, in surrounding pressure sealing relation, that portion of the wall of the high pressure chamber 55 in which are formed the ports 28 and 32. The valve casing 36 may be formed integral with the casing I6 and the bulkhead l9. An annular row of ports 31 is formed in that part of the valve casing 33 which is disposed in the high pressure chamber I8. The opposite end of the valve casing 36 is open to the low pressure chamber ll. Thus the high and low pressure chambers ii and i3 communicate through ports 3? of valve casing 35.

A valve piston 38 is slidingly fitted in the valve casing 36 and, when in position for normal operation of the turbine 3, is disposed to close the ports 37 thereby preventing communication between the high pressure chamber l8 and the low pressure chamber H. The valve piston 38 is biased toward the closed end of the valve casing 36 by means of a spring 39 and is held against the bias of the spring 39, during normal operation, by fluid pressure admitted to the valve casing 36 through port 32. The piston 33 is carried by a rod 4| which is provided with a reduced end portion 42 forming a shoulder 43. The reduced end portion 42 is slidably carried in a bore in the wall of the low pressure chamber IT. The shoulder is adapted to abut the wall of the chamber [1 when the piston 38 is in position for normal operation. The spring 35 is held in axial alignment with the piston 38 by a circular boss 44 formed on the wall of the low pressure chamber l|.

Apparatus for controlling the supplying and exhausting of pressurized fluid to and from control valve 9 comprises valve means 34 which is connected by a rod 63 with pilot valve means and is thereby operably connected to lever 6, the overspeed tripping mechanism 8 (see next paragraph) and pressure sealing means cooperating with the piston 38, here shown as a valve element 45 disposed on the lower side of the valve piston 38 in axial alignment with the port 28. The entrance of the port 23 is formed with a chamfer to provide a seating surface 46 for the valve element 45.

The overspeed tripping device 8 may be of any known design. It is here shown as comprising a valve 47 communicating with the lower end of the control valve casing 36 through the conduit 29 and branch conduit 33, with the pump 25 through conduit 29a, and with a drain 3|. The Valve 41 is normally held in a position permitting communication between the valve casing 36 and the pump 25 by a lever 50 pivoted at 48. A trip finger 49 pivoted at 5| engages the free end of the lever 56 during normal operation of the turbine 3. A spring loaded weight member 52 is mounted on the turbine shaft 53 with its center of mass spaced from the center of shaft 53 so that centrifugal force will move member 52 radially outward against the bias of the spring 5 when a predetermined overspeed of the turbine 3 is reached. When the weight member 52 so moves, it will strike the trip finger 49 and release the end of the lever 50 which in turn will permit a valve member 55 to move, under the bias of a spring 56, to a position which will close the conduit 290. leading from the pump 25 and permit communication between the valve casing 36 and the drain 3| through the port 28 and the conduit 29.

It will be apparent that the action of the valve 41 in cutting ofi fluid pressure from the passage 29a and the communication of the passage 29 with the drain 3| will result in the downward movement of the control valve piston 38 in the control valve casing 35 under the influence of the spring 39. Such downward movement of the control valve piston 38 will permit communication between low pressure chamber I! and high pressure chamber l8 through ports 3'! of control valve casing 36. The fluid beneath the motor piston II will escape through the port 23, the ports 37, the valve casing 36 and the low pressure chamber I1 and, enter the top of the motor cylinder through the port 2| and the spring M will move the motor piston ll downward thus closing the throttle valve l.

The pilot valve means 5 carries valve means 34 and both means are shown slidably disposed in a cylindrical pilot valve casing 51. Formed in casing 51 is a first annular groove 58 which communicates with the upper end of the motor cylinder I3 through the port 22, the low pressure chamber IT, and the port 2|. A second annular groove 59 formed in the casing 5! communicates with the lower end of the motor cylinder |3 through the port 35, the high pressure chamber l6 and the port 23.

A third annular groove 6| formed in the casing 51 communicates with the space beneath the valve piston 38 through the conduit 33 and the port 32. A port 62 formed in the casing 5! communicates with the conduit 29 through the conduit 33.

Valve means 34 is disposed above the annular groove 6| in normal operation and is adapted to cover the groove 6| when rod 63 is brought to its lowest position, as will more fully appear. Valve means 5 closes the upper end of the casing 57 and functions to throttle the fluid passing through the annular groove 58 to the low pressure chamber H. The annular groove 59 is disposed above valve means 34 and below valve means 5 and remains open and in communication with the high pressure chamber I8 through the port 35 at all times.

Valve means 5 and 34 are operably connected to floating lever 6 by a connecting rod 61. One end of floating lever 6 is pivotally connected to the piston rod |2 of the motor means 4 and the other end is pivotally connected to control means 69 which may comprise a rotatable threaded shaft journaled in bearings 12. A nut 13 is threaded on the shaft TI and is adapted to run along the shaft H when the shaft H is rotated. A pintle 14, carried by the nut 13, pivotally engages the floating lever 6. The nut 73 and pintle 14 may be considered to be the control member "I as its position will normally control the position of the throttle valve The shaft H may be rotated by a handwheel 15 mounted on the end of the shaft 1 The operation of the above described apparatus is as follows:

Fluid under pressure, supplied by the pump 25, flows through the conduit 26, the orifice 21, the port 24, the high pressure chamber [8 and the port 23 into the space beneath the motor piston ll. Fluid under pressure also flows from the high pressure chamber l8 through the port 35, the pilot valve casing 5'! and the port 22 into the low pressure chamber thence to the space above the piston H and to the drain Hi. The fluid flowing through the port 22 is throttled by p lot valve means 5. The fluid pressure in the high pressure chamber I8 and beneath the piston I will therefore be controlled by the position of pilot valve means 5.

Assume that the apparatus is in the position shown in the drawing and that it is desired to open the throttle valve I further. The control member I is moved downward by rotation of the handwheel I5. This causes pilot valve means 5 to be moved downward restricting the flow of fluid through the port 22. The throttling of the fluid passing through the port 22 will increase the fluid pressure in the high pressure chamber I8 and in the space beneath the motor piston II since the orifice valve 21 permits a definite amount of fluid to enter the high pressure chamber I8. This increased pressure acting on the motor piston I I will cause the motor piston I I to move upward against the bias of the spring I4 thus moving the throttle valve I in valve opening direction.

As the motor piston I I moves upward, the end of the floating lever 6 connected to the piston rod I2 also moves upward. This in turn causes pilot valve means 5 to move upwardly so as to progressively decrease the throttling of fluid through the port 22 until a state of equilibrium is reached and the fluid pressure acting on the motor piston II is balanced by the bias of the spring I4. The throttle valve I, will then be in a position corresponding to a definite setting of the control member I and if the throttle valve I is to be opened further, the control member I must be advanced or, as shown here, moved downward.

Assume the apparatus to be in the position shown in the drawing and that it is desired to move the throttle valve I toward the closed position. The control member I is moved upward by rotation of the handwheel 15. This will cause pilot valve means 5 to be moved upward and the port 22 to be opened. The decreasing of throttling at the port 22 will cause a decrease in fluid pressure beneath the motor piston II and the spring I4 will move the motor piston II downward thus moving the throttle valve I in valve closing direction. The downward movement of the motor piston I I will cause the downward movement of the end of the floating lever B which is connected to the piston rod I2 and this in turn will eflect the downward movement of pilot valve means 5. The downward movement of pilot valve means 5 will increase the throttling at the port 22 until the pressure under the motor piston II is once again sufl'icient to hold the piston II against the bias of the spring I4.

Assume that the throttle valve I is in any open position and the turbine 3 exceeds the predetermined maximum speed. Centrifugal force will move the weight member 52 radially outward against the bias of the spring 54. The weight member 52 will strike the trip finger 49 which will move about its pivot 5I and be disengaged from the lever 50. Release of the end of the lever 53 will permit it to move angularly about its pivot 48 and remove restraint from the valve 4I. The spring 56 will move the valve member 55 upward closing off the conduit 29a leading from the pump 25 and establishing communication between the space below the control valve piston 38 and the drain 3i through the conduit 29 and the port 23. This will release the fluid pressure beneath the control valve piston 38 and the spring 39 will move the control valve piston 38 downward until the valve element seats in the entrance of the port 28.

When the control valve piston 38 moves downward, the ports 31 are uncovered and communication is established between the high pressure chamber I8 and the low pressure chamber I! through the ports 31 of control valve casing 36. This provides a short path for the fluid which is released from beneath the motor piston II thereby permitting rapid flow of the fluid and insuring quick closing of the throttle valve I. Belease of fluid pressure from beneath the motor piston I Iv causes the spring I4 to move the motor piston II downward and thus close the throttle valve I.

When the throttle valve I is closed upon actuation of the tripping means 8 described above, the control member I will be in a position corresponding to some open position of the throttle valve I. Therefore, the end of the floating lever 6 which is connected to the control member I will be lower than it i when the throttle valve I is closed by movement of the control member 1. This low position of the floating lever 6 will result in the valve means 34 being carried to a correspondingly lower position relative to the casing 51 such that it will cover the annular groove BI which communicates with the space below the control valve piston 38.

Thus when the throttle valve I is closed through the operation of the tripping device 8, the space below the control valve piston 33 is isolated from fluid pressure by the valve element 45 seating in the entrance of the port 28 and by the closing of the groove BI by valve means 34 which is carried by pilot valve means 5.

Resetting of the tripping device 8 is accomplished by pivoting lever 53 and finger 49 about their respective pivots 48, 5I, until their adjacent ends engage each other as shown in the drawing. This will readmit fluid pressure to the conduits 29 and 33. However, the cross-sectional area of the valve element 45 is relatively small and therefore the force resulting from the fluid pressure acting on the valve element 45 will not be great enough to move the control valve piston 38 against the bias of the spring 39. It is apparent that the throttle valve I cannot be reopened as long as the control valve piston 38 is in a position which permits communication between the space above and the space below the motor piston II. It is also apparent that the valve piston 38 cannot be moved to a position to prevent such communication until valve means 34, carried by pilot valve means 5, is moved to uncover the groove GI and admit fluid pressure to the space below the control valve piston 38 for unseating the valve element 45. Since valve means 34 only moves in response to movement of lever B, the control member I must be moved to a position corresponding to a closed position of the throttle valve I in order to raise valve means 34 to uncover the groove 6|. When the control member I is so moved, the groove BI is uncovered and communication is established between the space beneath the control valve piston 38 and the conduit 29 supplying fluid under pressure through the port 62, the annular groove 5 I, the conduit 33 and the port 32; fluid pressure is applied to the control valve piston 38 and the control valve piston 38 is moved against the bias of the spring 39 to its normal operating position where the shoulder 43 of the rod 4| abuts the casing I3 and where the control valve piston 38 closes the ports 3'! and prevents communication between the high pressure chamber I8 and the low pressure chamber II.

From the above description, it will be apparent to those skilled inthe art that, with this invention, gradual restoration of pressure of motive fluid after tripping is assured with full manual control and that reopening of the throttle valve I while the control member i is in a position corresponding to an open position of the throttle valve is precluded.

From the foregoing it will also be apparent to those skilled in the art that the illustrated embodiment of the invention provides a new and improved operating mechanism for a throttle valve and accordingly accomplishes the objects of the invention. On the other hand, it will also be obvious to those skilled in the art that the illustrated embodiment of the invention may be variously changed and modified, or features thereof, singly or collectively, embodied in other combinations than those illustrated, without departing from the spirit of the invention or sacrificing all of the advantages thereof, and that accordingly the disclosure herein is illustrative only and the invention is not limited thereto.

It is claimed and desired to secure by Letters Patent:

1. A control mechanism comprising: fluid pressure supply means, a motor biased to move in a first direction, said motor means being hydraulically connected to said fluid pressure supply means and movable in a second direction in response to an application of fluid pressure to said motor; a pilot valve associated with said motor and movable to progressively open and closed positions controlling the rate of egress of pressure fluid from said motor; a controlling member selectively movable in different direc tions relative to an intermediate position; a lever associated with said motor, pilot valve and control member to progressively open said pilot valve to effect a movement of said motor in said first direction to effect a follow-up action of said pilot valve, and vice versa; a control valve operable separably from said pilot valve and movable from an open position to a closed position to control egress of fluid from said motor; biasing means associated with said control valve for urging said control valve to said open position; means including a dual fluid supply conduit and a fluid drain for controlling the flow of pressure fluid to and from said control valve, said fluid-controlling means including a movable first element effective in one position to connect said control valve with said fluid pressure supply means and effective in another position to connect said control valve with said fluid drain, and including a second element controllably positioned in one or" said dual conduits and connected to said lever for movement therewith, said second element being progressively movable between limiting positions opening and closing said one dual conduit in response to movement of said lever in opposite directions.

2. A control mechanism comprising: fluid pressure supply means, a motor biased to move in a first direction, said motor means being hydraulically connected to said fluid pressure supply means and movable in a second direction in response to an application of fluid pressure to said motor; a pilot valve associated with said motor and movable to progressively opened and closed positions controlling the rate of egress of pressure fluid from said motor; a controlling member selectively movable in diflerent direc tions relative to an intermediate position; a lever associated with said motor, pilot valve and control member to progressively open said pilot valve to eflect a movement of said motor in said first direction to effect a follow-up action of said pilot valve, and vice versa; a control valve operable separably from said pilot valve and movable from an open position to a closed position to control egress of fluid from said motor; biasing means associated with said control valve for urging said control valve to said open position; means including a dual fluid supply conduit and a fluid drain for controllingthe flow of pressure fluid to and from said control valve, said fluid-controlling means including a movable first element effective in one position to connect through one of said dual supply conduits said control valve with said fluid pressure supply means and eflective in another position to connect said control valve with said fluid drain, and including a second element controllably positioned in one of said dual conduits and connected to said lever for movement therewith, said second element being progressively movable between limiting positions opening and closing said one dual conduit in response to movement of said lever in opposite directions.

3. A control mechanism comprising: fluid pressure supply means, a motor biased to move in a first direction, said motor means being hydraulically connected to said fluid pressure supply means and movable in a second direction in response to an application of fluid pressure to said motor; a pilot valve associated with said motor and movable to progressively opened and closed positions controlling the rate of egress of pressure fluid from said motor; a controlling member selectively movable in different directions relative to an intermediate position; a lever associated with said motor, pilot valve and control member to progressively open said pilot valve to eflect a movement of said motor in said first direction to effect a follow-up action of said pilot valve, and vice versa; a control valve having a predetermined area which is subjected to pressure fluid and effective upon application of pressure fluid thereto to move said valve separably from said pilot valve from an open position to a closed position to control egress of fluid from said motor; biasing means associated with said control valve for urging said control valve to said open position; means including a dual fluid supply conduit and a fluid drain for controlling the flow of pressure fluid to and from said control valve, a valve element carried by said control valve adapted to close one of said dual fluid supply conduits when said control valve moves into fully open position, said fluid-controlling means including a movable first element effective in one position to connect said control valve with said fluid pressure supply means and effective in another position to connect said control valve with said fluid drain, and including a second element controllably positioned in one of said dual conduits and connected to said lever for movement therewith, said second element being progressively movable between limiting positions opening and closing said one dual conduit in response to movement of said lever in opposite directions, said valve element presenting an effective area which is incapable of moving said control valve away from its said fully open position when said second element is in a position closing said one dual conduit.

4. A control mechanism comprising: fluid pressure supply means, a motor biased to move in a first direction, said motor means being hydraulically connected to said fluid pressure supply means and movable in a second direction in response to an application of fluid pressure to said motor; a pilot valve associated with said 9 motor and movable to progressively opened and closed positions controlling the rate of egress of pressure fiuid from said motor; a controlling member selectively movable in different directions relative to an intermediate position; a lever associated with said motor, pilot valve and control member to progressively open said pilot valve to effect a movement of said motor in said first direction to effect a follow-up action of said pilot valve, and vice versa; a control valve having a predetermined area which is subjected to pressure fluid and effective upon application of pressure fluid thereto to move said valve separably from said pilot valve from an open position to a closed position to control egress of fiuid from said motor; biasing means associated with said control valve for urging said control valve to said open position; means for controlling the flow of pressure fluid to and from said control valve including a dual fluid supply conduit connected to said fluid pressure supply means and including a fiuid drain, a valve element carried by said control valve adapted to close one of said dual fluid supply conduits when said control valve moves into fully open position, said fluid-controlling means including a movable first element efiective in one position through one of said dual supply conduits to connect said control valve with said fluid pressure supply means and effective in another position to connect said control valve with said fluid drain, and including a second element controllably positioned in one of said dual conduits and connected to said lever for movement therewith, said second element being progressively movable between limiting positions opening and closing said one dual conduit in response to movement of said lever in opposite directions, said valve element presenting an effective area which is incapable of moving said control Valve away from its said fully open position when said second element is in a position closing said one dual conduit, the other of said dual fluid supply conduits bypassing said second element to hydraulically connect said control valve directly to said first element.

CLARENCE E. KENNEY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,017,557 Kieser Feb. 13, 1912 1,791,249 Schwendner Feb. 3, 1931 1,931,104 Caughey Oct. 17, 1933 2,285,208 Johntz June 2, 1942 2,380,705 Proctor July 31, 1945 2,530,659 Hill Nov. 21, 1950 

